A Butterfly's Eye View - UV Nectar Guides

While identifying the Queen Alexandra's Sulpur butterflies in our backyard, we read that they are also sometimes called UV Sulphur butterflies. The male butterflies reflect UV light to attract females - or something like that.  We didn't fully understand everything we read, but we wanted to check it out.

I made a quick butterfly net out of a hanger, and some netting, that came around our oranges, for the children...

...and sent them on a butterfly hunt.

Once we captured a specimen (and by we, I mean me - much to the amusement of our neighbors, I'm sure), we placed it into an empty fish bowl...

...so we could shine a UV flashlight onto it, in a dark room.  It sort of glowed, but not in anyway that was impressive, so I'm thinking there's more to it, than we were seeing or understanding.  Still, it was worth a try.

After we released our butterfly back into the wild, and watched it fly away, stunned but unharmed...

...we decided to take a look at one of the dandelions it was frequenting.  This time our UV light revealed something interesting.  The florets on the outer edge of the flower turned a light pink, while the center of the dandelion remained dark yellow.  After a little more research we found out this is called a nectar guide.

Butterflies, like bees, and a number of other insects, don't see the color red, but do see some UV light.  When viewed under a UV light, many flowers have patterns that indicate nectar, and draw insects in like a bullseye. 

We won't be looking at dandelions the same way again.  Who knew there were so many fascinating scientific discoveries waiting in our backyard?

Sources:
Wikipedia - "Ultraviolet Communication In Butterflies" and "Colias Alexandra"
Boston University - "Ultraviolet Patterns in Flowers, or Flowers as Viewed by Insects" by Richard B. Primack. This is a good one to read, if you're wondering how scientists know that insects can see UV light and not red.
PBS Kids - Fetch!: season 4, episode 13, "Is it a Bird? Is it a Plane? It's...Ruffmanman!"